1. Field of the Invention
The invention relates to a coupling device for the winding shaft of a safety belt with a retightening device, with flexible tension means which is in functional connection with a driving device, for instance a power accumulator, and with a tension means roll connected to the shaft to be driven.
2. Description of the Prior Art
In one known retightener for automatic safety belt winding devices with a power accumulator which can be released in the event of a crash as well as with an energy converter which acts on the belt shaft of the automatic winding device after the power accumulator is released and causes the former to execute a rotary retightening motion, a rotatable tension means roll is provided as the energy converter. This tension means roll can be coupled to the belt shaft such that, after the sensor-controlled activation of the power accumulator, the tension means are moved, for instance by a lifting cylinder, together with the tension means roll connected thereto. This tension means roll moves rolling bodies radially inward after shear pins are sheared off by a motion relative to the belt shaft and brings them into clamping and coupling engagement with the belt shaft. In normal operation, the tension means roll is therefore decoupled from the belt shaft and must execute a coasting rotation, if activated, for the purpose of coupling. The design of this known coupling device is relatively elaborate and must be relatively strong, with relatively large moving masses.